Antidiabetic Agents
Definition
Anti-diabetic drugs - lower glucose levels in the blood.
Except of insulin, all are administered orally and are thus also called oral hypoglycemic agents or oral antihyperglycemic agents.
Diabetes mellitus type 1 - caused by the lack of insulin. Insulin must be used in Type I, which must be injected or inhaled.
Diabetes mellitus type 2 - insulin resistance by cells. Treatment by
(1) agents which increase the amount of insulin secreted by the pancreas,
(2) agents which increase the sensitivity of target organs to insulin
(3) agents which decrease the rate at which glucose is absorbed from the gastrointestinal tract.
Several groups of drugs, mostly given by mouth, are effective in Type II, often in combination. The therapeutic combination in Type II may include insulin.
Insulin
Insulin is usually given subcutaneously
may also be given intravenously.
There are several types of insulin, characterized by the rate which they are metabolized by the body.
Secretagogues
Sulfonylureas
Meglitinides
Sulfonylureas
trigger insulin release by direct action on the KATP channel of the pancreatic beta cells.
May cause weight gain.
Sulfonylureas are only useful in Type II diabetes, as they work by stimulating endogenous release of insulin.
Best with patients over 40 years old, who have had diabetes mellitus for under ten years.
They can not be used with type I diabetes, or diabetes of pregnancy.
Safe to use with metformin or -glitazones.
First-generation agents
tolbutamide
acetohexamide
tolazamide
chlorpropamide (Diabinese)
Second-generation agents
glipizide (Glucotrol)
glimepiride (Amaryl)
gliclazide (Diamicron)
Meglitinides
Meglitinides help the pancreas produce insulin and are often called "short-acting secretagogues."
They are taken with meals to boost the insulin response to each meal.
repaglinide (Prandin) - The maximum dosage is 16 mg/day, taken 0 to 30 minutes before meals. If a meal is skipped, the medication is also skipped.
nateglinide (Starlix) - The maximum dosage is 360 mg/day, usually 120 mg three times a day (TID). It also follows the same recommendations as repaglinide.
Adverse reactions include weight gain and hypoglycemia.
Biguanides
Biguanides reduce hepatic glucose output and increase uptake of glucose by the periphery, including skeletal muscle. Amongst common diabetic drugs, metformin, a biguanide, is the only widely used oral drug that does not cause weight gain.
metformin (Glucophage). Metformin may be the best choice for patients who also have heart failure.
Metformin should be temporarily discontinued before any radiographic procedure involving intravenous iodinated contrast as patients are at an increased risk of lactic acidosis.
Metformin is usually the first-line medication used for treatment of type-2 diabetes. Initial dosing is 500 mg twice daily, but can be increased up to 1000 mg twice daily. It is also available in combination with other oral diabetic medications.
Thiazolidinediones
Thiazolidinediones (TZDs), also known as "glitazones," They influence insulin sensitive genes, leading to better use of glucose by the cells.
rosiglitazone (Avandia)
pioglitazone (Actos)
Alpha-glucosidase inhibitors
Alpha-glucosidase inhibitors are
They do not have a direct effect on insulin secretion or sensitivity.
These agents slow the digestion of starch in the small intestine, so that glucose from the starch of a meal enters the bloodstream more slowly, and can be matched more effectively by an impaired insulin response or sensitivity. These agents are effective by themselves only in the earliest stages of impaired glucose tolerance, but can be helpful in combination with other agents in type 2 diabetes.
Acarbose (Glucobay)
Side effects (flatulence and bloating).
They do have the potential to cause weight loss by lowering the amount of sugar metabolism
